Using phenyl methanesulfonate as an electrolyte additive to improve performance of LiNi0.5Co0.2Mn0.3O2/graphite cells at low temperature

Phenyl methanesulfonate (PhMS) is chosen as a film forming electrolyte additive to improve the performance of the LiNi0.5Co0.2Mn0.3O2/graphite cells at low temperature. Meanwhile, the interfacial performance of cathode and anode is also investigated. Moreover, the cell with PhMS additive presents better discharge capacity retention at low temperature. Meanwhile, the cell with 1 wt% PhMS exhibits excellent capacity retention after 100 cycles at 10 degrees C (73.8%), which is much higher than that of the specimen without the addition of PhMS (54.7%). In addition, the electrochemical impedance spectroscopy (EIS) results indicate that the presence of PhMS can reduce the impedance of cell under low temperature conditions. Furthermore, the cyclic voltammetry (CV) curves, EDS, TEM and XPS results reveal that PhMS can participate in the formation of solid electrolyte interphase (SEI) film on the graphite anode surface. Besides, the SEM analysis confirms that the graphite anode surface has less deposition of lithium ions and formation of lithium dendrite in the electrolyte with addition of PhMS. The electrolyte with PhMS additive is promising for the applications in LiNi0.5Co0.2Mn0.3O2/graphite cells at low temperature. (C) 2019 Elsevier Ltd. All rights reserved.